Nope, you’re measuring the coils’ resistance that is normally between where the spark plug connects and the “-“ of the battery or the metal of the engine. I just checked my 390 and it reads something like 30.000 ohms (30kohms).
You can also enlarge the gap of the spark plug to 1cm which corresponds to the normal condition in the engine to check it. Strong ignition can bridge up to 1,5cm.
But somehow this sounds more like faulty timing to me.
You really only changed oil for the right oil in the right amount? And around 1l oil came out?
Okay thanks Peter, I'll try to do that measurement this week. How would I check for a timing issue?
And yes it ran fine and then shut off after changing oil. Around 1L came out and I filled it up to right around the middle of the sight glass